Arming system

ABSTRACT

A system having shallow depth capabilities for arming a submerged ordnance device independently of hydrostatic pressure, including a block having a cylinder therein; a piston having a radial bore therethrough slidably mounted in the block to form an expansible chamber in the inner extremity of the cylinder; an electrically energizable gas generating squib in fluid communication with the expansible chamber to increase the pressure therein; a port in the block providing fluid communication between the expansible chamber and the external environment; an explosive slug positioned within the piston in the radial bore; portions of an explosive train disposed within a pair of bores in the block on diametrically opposite sides of the cylinder; and releasable restraining pins holding the piston in a first position.

United States Patent Belsley 1 1 June 17, 1975 ARMING SYSTEM Primary Examiner-Verlin R. Pendcgrass [75] manor: Kenneth Belsky silver Spring Attorney, Agent, or Fzrm-R. S. Scrascta; J. A. Cooke [73] Assignee: The United States of America as [57] ABSTRACT represented b th Secretary f m A system having shallow depth capabilities for arming N v W hi DC a submerged ordnance device independently of hydrostatic pressure, including a block having a cylinder [22] F'led: June18'1968 therein; a piston having a radial bore therethrough Appl. No.: 740,816

slidably mounted in the block to form an cxpansible chamber in the inner extremity of the cylinder; an electrically energizable gas generating squib in fluid communication with the expansible chamber to increase the pressure therein; a port in the block provid ing fluid communication between the expansible chamber and the external environment; an ei plosive slug positioned within the piston in the radial bore; portions of an explosive train disposed within a pair of bores in the block on diametrically opposite sides of the cylinder; and releasable restraining pins holding the piston in a first position.

3 Claims, 1 Drawing Figure ARMING SYSTEM BACKGROUND OF THE INVENTION This invention relates generally to ordnance arming systems and more particularly to an arming system having shallow depth capabilities for submerged ordnance devices.

In the past, many forms of apparatuses and methods have been proposed for safely arming explosive devices only upon the devices being submerged. Somewhat more sophisticated techniques have been developed in the more recent past for the arming of such submerged explosive devices in very shallow depths, whereby the arming function must necessarily be independent of the hydrostatic pressure. These prior art techniques include various types of electrical circuitry, chemical and quasi-chemical systems, and mechanical devices energized by the action of a liquid, such as water, on dia phragms, bellows, or pistons and by various other techniques. One prior art system utilizes the principle that shock waves are conducted more efficiently by a liquid medium, such as water, than a gaseous medium, such as air; that prior art system contemplates a spacial separation between the detonator and the booster by a distance sufficient to prevent detonation of the booster when the separating medium is air or other gaseous material but to effect detonation when the separating medium is water or other liquid material. This system has the shortcomings of, first, great expense in that the manufacturing tolerances are extremely critical to as sure accurate spacial separation and in that the explosive characteristics of the detonator and booster materials must be reproduced with a high degree of accuracy and, second, lack of flexibility since, once the hardware has been fabricated, only the particular detonator and booster materials for which it was designed may be used. In addition, such a system is armed merely by immersion and cannot be selectively armed in response to secondary stimuli; in short, there is no out-of-line safety feature, Moreover, the results of recent experiments appear to challenge the basic operation of the system.

In a second prior art technique, shallow depth arming of a submerged device is achieved by a motor driven liquid pump having the inlet thereof in communication with the ambient liquid within which the device is submerged and the outlet thereof in communication with a piston movable from an initial safe position to an armed position by the pressure of liquid thereagainst when the pump has increased the liquid pressure to a predetermined valve. This technique requires large, heavy, complex, and expensive mechanical equipment and has the operational shortcoming of a compara tively long response time caused by the unavoidable delay during the pumping and resultant pressure build Still another prior art apparatus contemplates an ignition train comprising an ignition charge, a base charge for detonating the main charge on the ordnance item, and a columnar transmission charge interconnecting the ignition and base charges, in which the transmission column diameter is less than the failure diameter when surrounded by gas, such as air, and greater than the failure diameter when surrounded by liquid, such as water.

A fourth prior art system incorporates a detonating fuse formed into a loop having a sufficiently narrow open neck at its base so that, in a gaseous medium, the brisance of detonation in one of the sections of the neck will rupture and scatter the adjacent section without sympathetically actuating it and, in a liquid medium, the detonation stimulus will be propagated without hiatus from one section through the loop to the adjacent section.

In the last two prior art systems, as in the first described herein, the chemistry of the detonating explosive used for the transmission column and detonating fuse, respectively, is extremely critical and close manufacturin g tolerances of such materials and of the associated hardware are required, thus increasing the cost. Also, as in the first system, the device is armed by the mere immersion into a liquid medium and cannot be selectively armed in response to another stimulus when, but only when, immersed in a liquid. Without some type of out-of'line safety feature, these systems are necessarily armed upon the mere immersion in a liquid and may, therefore, detonate prematurely during, for example, emplacement, in the case of shallow depth mines. Hence, such systems do not provide the desired degree of safety required in certain applications.

SUMMARY OF THE INVENTION Accordingly, one object of the invention is to provide a new and improved actuating system for submerged devices.

Another object of the invention is to provide a new and improved submerged ordnance arming system suitable for use in shallow, as well as deep, liquid depths.

Still another object of the present invention is to provide a new and improved submerged ordnance arming system which cannot be armed in a gaseous medium but which can be selectively armed in a liquid medium independently of the hydrostatic pressure of the liquid medium.

A further object of the instant invention is to provide a new and improved submerged ordnance arming system having shallow depth capability which may be selectively armed only when immersed in a liquid, and characterized by small size, light weight, simple operation, low cost, and short response time.

A still further object of this invention is the provision of a new and improved submerged ordnance arming system having shallow depth capability and characterized by a high degree of flexibility as to explosive mate rials.

Yet another object is to provide a new and improved submerged ordnance arming system having shallow water capability which is not armed merely by immersion in a liquid medium but which has immersion in a liquid as a necessary condition precedent to arming.

Briefly, in accordance with one embodiment of this invention, these and other objects are attained by providing a pressure increasing device, a piston for arming an explosive train, and a cavity therebetween having an open port in fluid communication with the ambient environment whereby actuation of the pressure increasing device in a gaseous medium, such as air, will not transmit enough pressure to the piston to drive it from its safe, out-of-line position to its armed, in-line position, but in a liquid medium, such as water, will drive the piston from its safe to its armed position.

BRIEF DESCRIPTION OF THE DRAWING A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the followed detailed description when considered in connection with the accompanying drawing wherein the single FIGURE is an elevation view, partly in section, of a preferred embodiment of the ordnance arming system according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the ordnance arming system of the present invention is shown generally by the reference numeral as comprising a generally cylindrical body member 12 having an external flange 14 at the upper extremity thereof and an annular groove 16 therearound for accommodating a sealing device, such as O-ring 18, so that the ordnance arming system may be sealingly secured into a cylindrical bore (not shown) provided in a submerged ordnance device (also not shown) to be actuated thereby. A radial bore 20 extends through a major portion of body member 12 and is internally threaded at the outer extremity thereof. Body member 12 is provided with a longitudinally extending bore 22 formed centrally in the upper extremity thereof thereby forming a cavity to accommodate a power supply, such as a seawater battery (not shown). Another longitudinal bore 24 having a substantially greater diameter than bore 22 and in communication therewith is formed in the upper extremity of body member 12 of a depth substantially less than bore 22. Still another longitudinal bore 26 having a slightly larger diameter than bore 24 is formed in the upper extremity of body member 12 and has a depth somewhat less than bore 24. A pair of internal annular grooves 28 and 30 are provided in body member 12 in the central portion of bore 26. A cover member 32, having a round flat, thin, disc portion 34 of a diameter slightly less than that of bore 26 and an integral thin hollow cylindrical protruding portion 36, is secured against a shoulder 38 formed by the termination of bore 26 by a retaining ring 40 seated in annular groove 28.

A longitudinal bore 42 is formed in body member 12 which extends from the upper extremity thereof and terminates before intersecting radial bore 22. Bore 42 is provided with an internal annular groove 44 near its upper extremity. An annular aperture 45 of substan tially the same diameter as that of bore 42 is provided in disc portion 34 of cover member 32 which is coaxially aligned with respect to bore 42.

A bore 46 is axially formed through body member 12 and intersects radial bore 20 near the middle thereof at a reduced diameter mid-portion 48 thereof. Still an other longitudinal bore 50 extends from the upper extremity of body member 12 until it intersects radial bore 20 near the inner extremity thereof. An annular aperture 52 of substantially the same diameter as that of bore 50 is provided in disc portion 34 of cover member 32 in alignment with bore 50. A further longitudinal bore 54 having a reduced diameter portion 56 extends from the lower extremity of body member 12 until it intersects radial bore 20 near the inner extremity thereof at said reduced diameter portion.

Slidably mounted within radial bore 20 is a generally cup-shaped piston member 58 having a radial bore 60 extending therethrough and an annular external groove 62 formed therein. A conventional sealing device, such as O-ring 64, is positioned within groove 62 and bears against the wall of radial bore 20 thereby providing a fluid tight seal therebetween.

Secured to piston member 58 by any conventional means, such as threaded connection 66, is an elongate shaft 68 having a reduced end portion 70. A stop nut 72, having an elongate, hollow reduced cylindrical protruding portion 74, is threadly secured within radial bore 20 and circumscribes shaft 68 which passes therethrough. Reduced portion 74 is of a sufficiently small diameter to slidingly fit within hollow cup portion 76 of piston member 58. A plurality of shear pins 78 extend through the walls of piston member 58 and bear against protruding portion 74 when the device 10 is in the safe or out-of-line position illustrated, thus preventing longitudinal movement of the piston member from the safe to the armed position. A retaining ring 80, having an annular opening 82 of a diameter slightly less that that of shaft 68 but slightly greater than that of reduced por tion thereof, is secured against stop nut 72 by an externally threaded lock nut 84. Piston member 58 also has a thin elongate extended portion 86 having an aper ture 88 extending therethrough which is in alignment with bore 50 and aperture 52 when the piston is in the safe position, as illustrated.

The explosive train of the arming system comprises a detonating device, such as an electro-responsive explosive actuator 90, positioned in bore 46 above re duced portion 48 and radial bore 20, an elongate train 92 of conventional explosive material positioned in bore 46 below reduced portion 48 and radial bore 20, and a slug 94 of similar explosive material positioned within bore 60 of piston member 58. In the illustrated safe position, a premature detonation of explosive actuator will not be communicated to explosive train 92. However, the sliding piston assumes an armed position upon movement when it abuts stop nut 72 since in such a position, the explosive actuator 90, the elongate train of explosive material 92, and the slug 94 of explosive material all are substantially aligned, and a detonation of explosive actuator 90 will be propagated through elongate train 92 to the main explosive charge (not shown) of the submerged ordnance device (also not shown).

To increase the gaseous pressure within the inner extremity of radial bore 20 to thereby drive the piston, an electrically energizable gas generating squib 96, is secured within bore 54 against reduced portion 56 by any conventional means, such as an externally threaded hollow retaining nut 98. An integral safety pin and cap arrangement 100, comprising a flat circular disc portion 102 having welded or otherwise secured thereto an elongate circular rod portion 104 with an external nipple 106 on the lower extremity thereof and a pull ring 108 on the upper extremity thereof, is included to pro vide a plurality functions as will be described more fully hereinafter. A conventional sealing device, such as O- ring 110, positioned in groove 30 effects a fluid tight seal between body member 12 and disc portion 102 which is initially seated against retaining ring 40. A nipple 106 is pressed through aperture 88 thereby providing the dual function of precluding the safety pin and cap arrangement from accidentally falling out and additionally securing piston member 58 thusly preventing premature arming independently of shear pins 78. Disc portion 102 also serves to urge a rod 112 positioned in bore 42 inwardly against a resilient device, such as compressed coil spring 114, thereby holding a micro-switch 116 in an open circuit position when the safety pin and cap arrangement are in place as shown Micro-switch 116 electrically interconnects squib 96 and its power supply (not shown) and in the open position provides an additional safety by preventing premature activation of squib 96. A conventional sealing device, such as O-ring 118, positioned within groove 44 provides a fluid tight seal between body member 12 and rod 112.

The operation of the arming system of the present invention may be better understood by the following de scription in conjunction with the drawing wherein the system is illustrated in its safe, or out-of-line, position. The illustrated position is considered safe because, as heretofore described. slug 94 of explosive material within bore 60 of piston member 58 is out-of-line with respect to explosive actuator 90 and elongate train 92 of explosive material whereby a premature detonation of the explosive actuator can not be communicated to the elongate train or to the main explosive charge therebelow (not shown) of the underwater ordnance device (also not shown). Displacement of piston member 58 along its axis is precluded, first, by shear pins 78 passing through and secured to the piston member and bearing against reduced cylindrical portion 74 of stop nut 72 and, second, by the engagement of rod portion 104 of safety pin and cap arrangement 100 within aperture 88 provided in extended portion 86 of piston mem ber 58.

Unintentional withdrawal of safety pin and cap arrangement 100 from its illustrated position is prevented by nipple 106 which necessitates a positive force in the upward direction, preferably exerted on pull ring 108, at the desired time in order to displace the safety pin and cap arrangement. O-ring I positioned in groove 30 effects a fluid tight seal between body member 12 and disc portion 102 of the safety pin and cap arrange ment to prevent liquid entry into bore 50 and/or the inner extremity of bore if the system should be submerged before the safety pin and cap arrangement have been withdrawn. Moreover, with the safety pin and cap arrangement in the illustrated position, micro-switch 116 is maintained in its open circuit condition by rod 112.

When safety pin and cap arrangement 100 is withdrawn by an upward force on pull ring 108, piston member 58 is freed of one of its restraints, namely, rod 104, but is still restrained by shear pins 78. It should be understood that it may be necessary to provide appropriate venting and sealing to the cup-shaped end of the piston member if the arming system is to be used in excessively deep depths, since the large hydrostatic pressures at such depths may otherwise sever shear pins 78 and drive the piston member into the armed position before the arming is desired. With the safety pin and cap arrangement withdrawn, spring 114 urges rod 112 upward thereby closing micro-switch 116', however, squib 96 is not thereby actuated since its power supply may be a seawater battery (not shown) which is still dry and/or there may be still another switch (also not shown) in the circuit which will enable the system to become armed at the command of an observer or other stimuli. With the safety pin and cap arrangement removed but while the arming system is in a gaseous environment, ignition of squib 96 will not arm the system since the generated gases will compress some of the gas in bores 24 and S0 and will cause the remainder to vent out through bore 50; the result, with gas in bores 20 and 50, is that the pressure increase caused by squib 96 is not sufficiently high to transmit enough shock to piston member 58 to sever shear pins 78 and drive the former to its armed or in-line position. However, when the arming system is immersed in a liquid, the liquid medium fills bores 20 and 50 whereupon actuation of squib 96 and the resultant pressure increase of the expanding gases will cause shear pins 78 to fail and piston member 58 to slide to the right to its armed, in-line, position. Retaining ring 80 having opening 82 of a diameter slightly smaller than that of shaft 68 provides a frictional lock on shaft 68 in the armed position thereby preventing bounceback to the left of the piston member to an out of alignment position. Thus, the arming system of the present invention has completed its operation. It should be understood that the detonating of explosive actuator 90, slug 94, elongate train 92, and main explosive charge (not shown) forms no part of the present invention and may be accomplished by a variety of conventional techniques. It has been found that an arming system according to the present invention operates virtually independent of hydrostatic pressure and functions properly when submerged in water at depths as low as six inches.

Obviously, numerous modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An arming system comprising:

a block member having a first bore therein and a second bore therein, said second bore opening from the exterior surface of said block member and extending into a first extremity of said first bore providing open fluid communication between said first bore and the external environment;

an explosively laden piston member slidably positioned within said first bore in an initial position defining an expansible chamber at said first extremity of said first bore;

pressure increasing means in fluid communication with said expansible chamber operable under conditions defined solely by said second bore in said expansible chamber being filled with a predetermined amount of ambient liquid for moving said piston member from said initial position to a prede termined second position; and

means for restraining said piston member at its position of maximum movement including a retaining ring positioned within said first bore having an aperture therein and a shaft member fixed longitudinally to said piston member having a diameter slightly larger than said aperture,

whereby when said piston member moves to said second position said aperture receives said shaft member providing a frictional fit thereby preventing said piston member from returning to said initial position.

2. An arming system comprising:

a block member having a first bore therein and a second bore therein, said second bore opening from the exterior surface of said block member and extending into a first extremity of said first bore pro viding open fluid communication between said first bore and the external environment;

an explosively laden piston member slidably positioned within said first bore in an initial position de fining an expansible chamber at said first extremity of said first bore; and

pressure increasing means in fluid communication with said expansible chamber operable under conditions defined solely by said second bore and said expansible chamber being filled with a predetermined amount of ambient liquid for moving said piston member from said initial position to a predetermined second position, said piston moving means including an electrically energizable gas generating squib positioned in fluid communication with said expansible chamber.

3. An arming system comprising:

a block member having a first bore therein and a second bore therein, said second bore opening from the exterior surface of said block member and extending into a first extremity of said first bore providing open fluid communication between said first bore and the external environment;

an explosively laden piston member slidably positioned within said first bore in an initial position defining an expansible chamber at said first extremity of said first bore;

pressure increasing means in fluid communication with said expansible chamber operable under conditions defined solely by said second bore and said expansible chamber being filled with a predetermined amount of ambient liquid for moving said piston member from said initial position to a predetermined second position; and

detachable means for fluidly sealing off said second bore and said expansible chamber from the external environment comprising means for selectively restraining said piston member from movement. 

1. An arming system comprising: a block member having a first bore therein and a second bore therein, said second bore opening from the exterior surface of said block member and extending into a first extremity of said first bore providing open fluid communication between said first bore and the external environment; an explosively laden piston member slidably positioned within said first bore in an initial position defining an expansible chamber at said first extremity of said first bore; pressure increasing means in fluid communication with said expansible chamber operable under conditions defined solely by said second bore in said expansible chamber being filled with a predetermined amount of ambient liquid for moving said piston member from said initial position to a predetermined second position; and means for restraining said piston member at its position of maximum movement including a retaining ring positioned within said first bore having an aperture therein and a shaft member fixed longitudinally to said piston member having a diameter slightly larger than said aperture, whereby when said piston member moves to said second position said aperture receives said shaft member providing a frictional fit thereby preventing said piston member from returning to said initial position.
 2. An arming system comprising: a block member having a first bore therein and a second bore therein, said second bore opening from the exterior surface of said block member and extending into a first extremity of said first bore providing open fluid communication between said first bore and the external environment; an explosively laden piston member slidably positioned within said first bore in an initial position defining an expansible chamber at said first extremity of said first bore; and pressure increasing means in fluid communication with said expansible chamber operable under conditions defined solely by said second bore and said expansible chamber being filled with a predetermined amount of ambient liquid for moving said piston member from said initial position to a predetermined second position, said piston moving means including an electrically energizable gas generating squib positioned in fluid communication with said expansible chamber.
 3. An arming system comprising: a block member having a first bore therein and a second bore therein, said second bore opening from the exterior surface of said block member and extending into a first extremity of said first bore providing open fluid communication between said first bore and the external environment; an explosively laden piston member slidably positioned within said first bore in an initial position defining an expansible chamber at said first extremity of said first bore; pressure increasing means in fluid communication with said expansible chamber operable under conditions defined solely by said second bore and said expansible chamber being filled with a predetermined amount of ambient liquid for moving said piston member from said initial position to a predetermined second position; and detachable means for fluidly sealing off said second bore and said expansible chamber from the external environment comprising means for selectively restraining said piston member from movement. 